How to Install a Surface Water French Drain

by Denise Brown

Water standing around the foundation of your house is not a good thing. Since water flows downhill, that standing water is trying to find the path of least resistance into your dry basement. To solve the problem, you must devise a different path for the water to run away from your basement. A French drain is a good solution. This wide, shallow trench allows surface water drainage, yet is simple enough to install. The hardest part of the task is digging the trench. Call the local utility companies to mark their buried lines on your property several days before begin installation of the drain.

1

Walk around your yard after a heavy rain to determine where the low spots are. Visualize a path for your French drain tile system that flows from the wet spot to a lower spot. The French drain needs at last a 1 percent drop. A 1-foot drop per 100 feet is adequate to create that. For example, a 20-foot drain needs to drop slightly more than 2 inches.

2

Mark the drainage path with string and stakes or spray paint. Dig a U-shaped trench 8 inches wide, starting at the lowest point. Make the trench at least 8 inches deep. Either dig the trench with a shovel if it’s a short distance, or rent a trencher to dig a longer French drain system. If you encounter rocks or tree stumps, it’s easier to adjust the slope as you work up the grade.

3

Add 2 inches of clean 1-inch gravel to the base of the trench. Avoid using limestone, as its dust becomes cement-like when it’s wet. Lay 4-inch drainage tile in the trench with the perforations facing down. Slide male couplers inside the tile to connect them, as necessary. Add enough gravel under the upper end of the tile so that its opening is at ground level. Cover the upper end with a cap, so you can clean the tile out whenever it becomes necessary.

4

Slip a tile sleeve onto the length of the tile. The sleeve helps prevent the perforations from clogging. Wrap water-permeable landscape fabric around the tile as well to give it extra protection from silt and sand that may enter the drainage system.

5

Center the tile in the trench. Set a carpenter’s level on the tile in several locations to ensure that it has a good downward slope along its length.

6

Add gravel on both sides of the trench to keep the tile centered. Place an additional 2 inches of gravel on top of the tile to fill the trench.

7

Spread coarse sand over the top layer of gravel. Smooth it out. If desired, plant grass seed in the sand or cover the sand with fresh sod. Rinse the soil off the sod’s roots before setting it, so the dirt doesn’t filtrate into the French drain.

About the Author

Denise Brown is an education professional who wanted to try something different. Two years and more than 500 articles later, she's enjoying her freelance writing experience for online resources such as Work.com and other online information sites. Brown holds a master's degree in history education from Truman State University.

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